CHAPTER EIGHT
CHAPTER OBJECTIVES
► Know how modern fingerprint analysis is used in the identification of suspects.
► Know the mechanics and accuracy levels of voice identification techniques.
► Know the basic approaches to using the polygraph test.
KEY TERMS
Sir Francis Galton Galton’s Details
Dactyloscopy IAFIS
Confirmation bias Polygraph
Control question test Guilty knowledge test
Scientific profiling Cantor model
LECTURE NOTES
Fingerprints
Fingerprints have been discovered on ancient Babylonian clay tablets, seals, and pottery.
They have also been found on the walls of Egyptian tombs and on Minoan, Greek, and
Chinese pottery. On some pottery, fingerprints were impressed so deeply that they were
likely intended to serve as the equivalent of a brand label (Laufer, 1912; Ashbaugh, 1999;
Åström, 2007).
By 246 B.C.E., Chinese officials impressed their fingerprints in clay seals, which were
used to seal documents. With the advent of silk and paper in China, parties to a legal
contract impressed their handprints on the document. All told, even in the first century it
was recognized that fingerprints are unique to each person and cannot be imitated. This is
not always the same with physical appearances or handwriting. In addition, fingerprints do
not change naturally over time. Furthermore, despite the attempts of modern day criminals
to efface their prints with sandpaper or acid, they cannot be disguised or permanently
altered.
He is also credited with the first fingerprint identification: a greasy print left by a laboratory
worker on a bottle of alcohol. Soon, Faulds began to recognize that the distinctive patterns on
fingers held great promise as a means of individual identification. He further developed a
classification system for recording these inked impressions.
Faulds described the pattern formations on the fingers, referred to “loops” and “whorls” and
stating how good sets of fingerprints may be obtained by the use of “a common slate or
smooth board of any kind, or a sheet of tin, spread over very thinly with printer’s ink. Faulds
correctly concluded that fingerprints do not change and that “fingermarks” (that is, latent
prints) left on objects by bloody or greasy fingers may lead to the scientific identification of
criminals (Adelmann, 1966).
Galton classified fingerprints by general shape (arch, loop, or whorl), position in finger, and
relative size. The arch fingerprint shape is formed by ridges interring from one side of the
pattern, rising in the center (in an arch like fashion), and flowing out the other side of the
pattern. In the loop fingerprint shape, ridges enter one side of the pattern, recurve (turning
back to the direction of entry), and exit the pattern. If the ridges of the pattern area slant
toward the thumb, the pattern is termed a radial loop. If the ridges of the pattern area slant
toward the little finger, the pattern is called an ulnar loop. The whorl fingerprint shape
consists of a pattern of ridges which encircle a central circular pattern (Galton, 1892). Galton
discovered that his arch, loop, and whorl details are not continuous, but rather, contain
Procedures for Collecting Fingerprints
The study of fingerprint patterns for the purpose of making identifications is called
dactyloscopy.
Dusting
Fingerprint lifting tape
The most common method of collecting latent fingerprint evidence after powdering. After the
Episcopic coaxial illumination
This technique involves the use of a semi-transparent mirror to observe the reflection of light
Lasers
A laser is sometimes used in the forensic setting to detect fingerprints which could not be
detected through the use of powders, iodine, silver nitrite, or ninhydrin. In this process, a laser
Integrated Automatic Fingerprint Identification System (IAFIS)
In 1999 the FBI and the law enforcement community developed the Integrated Automated
Fingerprint Identification System (IAFIS), which maintains the largest biometric database in
the world, containing the fingerprints and corresponding criminal history information for more
than 55 million subjects in the Criminal Master File.
The Limits of Fingerprint Evidence
David Stoney, a forensic scientist and distinguished expert on fingerprints asserts that the best
answer to the question ‘how much correspondence between two fingerprints is enough to
determine a match’ is that “this is up to the individual expert fingerprint examiner to determine,
(Risinger, Saks, Thompson, and Rosenthal, 2002). More specific to errors in fingerprint
analysis, there is research to show that such errors result from the way the brain processes
information and makes decisions (Cole, 2005; Dohr, 2005; Dohr, Charlton, and Peron, 2006;
Stacey, 2004).
Voice Identification
The question of how well lay witnesses like Lindbergh can recognize voices arises regularly in legal
cases. When a woman is sexually assaulted by a man wearing a ski mask, or when a government
The Mechanics of Voice Identification
The process involves the use of both aural and visual senses.
The first step is to evaluate the recording of the unknown voice, checking to make sure the
recording has a sufficient amount of speech with which to work and that the quality of the
recording is of sufficient clarity in the frequency range required for analysis. The volume of the
recorded voice signal must be significantly higher than that of the environmental noise. The
The visual process of voice sample comparisons involves a spectrographic analysis of the
recorded samples. The sound spectrograph is an automatic sound wave analyzer with a high
quality, fully functional tape recorder. The speech samples to be analyzed are recorded on the
sound spectrograph. The recording is then analyzed in two and one half second segments.
The product is a spectrogram, a graphic display of the recorded signal on the basis of time and
frequency with a general indication of amplitude. The spectrograms of the unknown speaker
are then visually compared to the spectrograms of the suspects.
Research and Admissibility
As far as admissibility of voice identification evidence into court is concerned, it is primarily
those jurisdictions utilizing the Daubert standard which allows such evidence into testimony. As
discussed in chapter two, under this standard a judge may admit such evidence if it will assist the
finder of fact (the jury) in better understanding the case as a whole.
Polygraphs
History
The modern polygraph has been used in one form or another for nearly a century, and much
cruder versions of its components existed as far back as 300 B.C.E. The Bedouins of Arabia, for
The first use of a scientific instrument designed to measure physiological responses for the
purpose of detecting deception came in 1895 when Italian physician, psychiatrist and pioneer
criminologist Cesare Lombroso modified an existing instrument called a hydrosphygmograph
and used this modified device in his experiments to measure the physiological changes that
occurred in a crime suspect’s blood pressure and pulse rate during a police interrogation.
Three basic approaches to the polygraph test
The Control Question Test (CQT)
The CQT compares the physiological response to relevant questions about the crime with the
response to questions relating to possible prior misdeeds. For example, (e.g., a question in a case
involving alleged child sexual abuse, “Did you insert your finger in Susan’s vagina?”) with
irrelevant questions covering inconsequential topics for which the correct answer was readily
apparent (“Is today Tuesday?”).
Without ever making a distinction between the control and relevant questions, the examiner
then introduces possible control questions that the subject also agrees are reasonably worded
and can be answered unambiguously; for example, “Have you ever lied to a person in a position
of authority?” Because the examiner admonishes the subject that the test will only work if the
subject is completely truthful, many subjects, when confronted with a control question like this,
The Directed Lie Test (DLT)
The DLT tries to detect lying by comparing physiological responses when the subject is told
to deliberately lie to responses when they tell the truth.
Guilty Knowledge Test (GKT)
The GKT compares physiological responses to multiple-choice type questions about the crime,
one choice of which contains information only the crime investigators and the criminal would
Evaluation of the Polygraph Technique
The justification for using the polygraph as a lie detector derives from the observation that
many people do indeed reveal increased physiological arousal at the moment they tell a lie. But
the majority of the scientific evidence indicates that
whatever accuracy the polygraph
Countermeasures
One of the problems with polygraphs is its susceptibility to countermeasures used by examinees
to fool the machine and the examiner (Bartol and Bartol, 2004). Countermeasures can be
physical or psychological. The most common countermeasures utilized are either pain or muscle
tension. For example, in an effort to deceive the polygrapher, “biting one’s lip or tongue or
subtly jabbing oneself with a pin may induce enough pain to promote a physiological response
that masks the subject’s response to questions from the polygrapher” (Bartol, p. 86).
Hypnosis
History
In the late eighteenth century, Franz Anton Mesmer experimented with “magnetic healing.”
In 1843, James Braid published Neurypnology; or, the Rationale of Nervous Sleep, Considered
in Relation with Animal Magnetism. In it, he described a state of nervous sleep as
“hypnotism“and substituted fixation of a luminous object, for the “magnetic process” used by
his predecessors.
Memory Enhancement
Memory enhancement is the use of hypnosis (usually by law enforcement and prosecutors) to
uncover memories often associated with criminal trauma.
Hypnoinvestigations
Hypnosis and Admissibility
Problems with the Reliability of Hypnotically-Refreshed Recall
1. A person undergoing hypnosis becomes more susceptible to suggestion. The subject
2. A hypnotized person may confabulate, that is, fill in the gaps in his/her memory to
3. Hypnotically-refreshed individuals often show “memory hardening,” in which the
subject adopts enhanced confidence in the facts remembered, whether they be true or
false (People vs. Hughes, 1983). Such courts point to scientific research indicating that
confidence in their statements which is non–deserved (Slovenko, 2002).
4. After undergoing hypnosis to refresh memory, individuals may lose the ability to
The Per Se Inadmissible Approach
As of 2010, two-thirds of all states (including California) consider hypnotically refreshed
testimony as per se inadmissible and bar its use altogether.
The Per Se Admissible Approach
Totality of the Ciurcumstances Approach (State v. Hurd, 1981)
But more and more states are adopting a middle ground approach requiring the use of procedural
safeguards which tend to reduce the potential inaccuracies of post-hypnotic testimony (see, e.g.
State v. Hurd, 1981, and Rock v. Arkansas, 1987).
In State v. Hurd (1981) the federal appeals court stated:
Second, the professional conducting the hypnotic session should
be independent of and not regularly employed by the prosecutor,
investigator or defense. This condition will safeguard against
any bias on the part of the hypnotist that might translate into
leading questions, unintentional cues, or other suggestive
conduct.
carefully avoid influencing the description by asking
structured questions or adding new details.
Fifth, all contacts between the hypnotist and the subject
must be recorded. This will establish a record of the pre-
induction interview, the hypnotic session, and the post–
hypnotic period, enabling a court to determine what
information or suggestions the witness may have received
during the session and what recall was first elicited through
hypnosis. The use of videotape, the only effective record
of visual cues, is strongly encouraged but not mandatory.
Hypnosis as a Means of “Inducing” Criminal Behavior
The notion that hypnotized persons can be induced to commit immoral, criminal, or self-
injurious acts of which they would normally be incapable has not received empirical
support.
Hypnosis and the Multiple Personality Disorder Defense
This has not met with success. One of the most famous examples is that of Ken Bianchi, who
tried without success to claim that his alter personalities (“Steve,” “Billy” and others) were
responsible for Bianchi’s nine killings from 1977 to 1979.
The Cognitive Interview
A technique used by “hypnoinvestigators” to enhance memory recall is designed to fully
immerse a subject in a partially-recalled situation using “freedom of description” rather than
Psychological Profiling
History
The Italian physician Cesare Lombrosos is generally credited with launching the scientific era in
criminology. In 1872 he differentiated five types of criminals— the born criminal, the insane
criminal, the criminal by passion, the habitual criminal, and the occasional criminal, all of
which were primarily based on Darwin’s theory of evolution.
Classification of Crime
Types of Offender Behavior at a Crime Scene
Modus Operandi (“M.O.”)
These are the functional components which are necessary for an offender to be successful in
committing a crime. These can include such things as; the time of day an offender, preferred
Signature (“Personation” or “Calling Card”)
These are behaviors that go beyond what is necessary to commit the crime to the fulfillment of a
Ritual
Ritual indicates a combination of fantasy and motivational factors which are psychologically
based and fulfill a need of the offender but which may not be necessary for the successful
Staging
Staging occurs when someone purposely alters the crime scene prior to the arrival of the police
usually in order to obscure the underlying motive of the crime. Staging may also occur when
someone desires to protect the decedent or the decedent’s family. This can occur in rape-murder
cases, domestic homicide, or “autoerotically-induced accidental deaths.
Modern Profiling
Non-scientific models of Criminal Profiling
These models provide primarily an intuitive analysis of crime scene evidence where proficiency
is a “gift reserved to certain individuals who can reach inside the criminal mind and understand
it.” (Holmes and Holmes, 1996, p.166). The basic approach of the Holmes and Holmes model
is to match case evidence to various criminal typologies (e.g. disorganized asocial versus
organized nonsocial offenders).
Scientific models of Criminal Profiling
This model, such as that proposed by Cantor (2000) stresses the importance of linking behaviors,
personalities, and other human characteristics to the commission of crime. In order for there to
be an empirically-based model of profiling, there must be a reliable relationship between actions
SUMMARY
Fingerprints have been discovered on ancient Babylonian seals as well as on the walls of
Egyptian tombs, and were apparently used as substitutes for signatures. One of the first great
contributors to the study of fingerprints was Sir Francis Galton who published his book Finger
Prints in 1892 presenting his collection of over 8,000 sets of prints. Galton classified
fingerprints by general shape (arch, loop, or whorl), position in finger, and relative size. One of
The technique of voice identification was first introduced in the American courts in the
mid 1960’s and has frequently been used as evidence in the courtroom. For practical purposes,
memory for brief voice samples is quite poor, and its admissibility into court is limited to those
jurisdictions utilizing the Daubert standard which allows a judge to admit evidence if it will
assist the jury in better understanding the case as a whole.
The first practical use of a scientific instrument designed to measure physiological
responses for the purpose of determining truthtelling was in 1895 when Cesare Lombroso
modified an existing instrument called a hydrosphygmograph and used this modified device in
his experiments to measure the physiological changes that occurred in a crime suspect’s blood
pressure and pulse rate during a police interrogation.
characteristics is established by asking the subject questions whose answers the investigator
knows. Deviations from the baseline for truthfulness are usually taken as signs of lying. One of
the problems with polygraphs is its susceptibility to “countermeasures” used by examinees to
fool the machine and the examiner. The most common countermeasures utilize are either pain
(e.g., biting one’s lip or longue) or muscle tension. Almost all courts reject polygraph results or
only admit them if their admissibility is stipulated by both parties prior to the polygraph
examination taking place. Only a few courts leave their admissibility up to the judge.
There are three basic types of offender behavior that may be exhibited at a crime scene –
modus operandi (“MO”), signature (or “personation” or “calling card”), and ritual. The term
modus operandi represents the functional components which are necessary for an offender to be
successful in committing a crime. Signature aspects of a crime, also referred to as personaltion
or calling card, are behaviors that go beyond what is necessary to commit the crime and fulfill a
psychological need of the offender. Ritual is a combination of psychologically-based fantasy
and motivational factors used to fulfill a need of the offender but which may not be necessary for
REVIEW QUESTIONS
1. What are the three basic shapes which Galton used to classify fingerprints?
2. What is “dactyloscopy?”
5. What is “IAFIS?”
6. What does the 2001 case of Commonwealth v. Cowans stand for?
7. How does The Mayfield Affair in 2004 demonstrate the limits of fingerprint
evidence?
13. What kinds of individuals have been known to “fool” the polygraph test?
14. What are “countermeasures” and how are they used?
15. What is the significance of the United States Supreme Court case of U.S. v. Scheffer
(1998) regarding polygraph admissibility?
16. What are the two broad areas in which hypnosis is used in investigations?